Pharmacokinetics, surrogate efficacy and safety evaluations of a new human plasma-derived fibrinogen concentrate (FIB Grifols) in adult patients with congenital afibrinogenemia

Abstract Background and aims Congenital afibrinogenemia is a rare coagulation disorder resulting from a deficiency in fibrinogen. This study assessed the pharmacokinetics, surrogate efficacy and safety of FIB Grifols, a new human plasma-derived fibrinogen concentrate, to treat congenital afibrinogenemia. Methods Eleven adult patients from a multinational, phase 1–2, prospective, open-label, single-arm, uncontrolled clinical study received a single infusion of FIB Grifols, 70 mg/kg bw. Fibrinogen pharmacokinetics (fibrinogen activity: Clauss method; antigen plasma concentrations: ELISA) and efficacy parameters were determined over 14 days after infusion. Efficacy endpoints were the mean change on plasma maximum clot firmness (MCF) on viscoelastic testing and coagulation tests 1-hour post-infusion, and correlation with fibrinogen levels throughout. Safety parameters were also assessed. Results For the Clauss method, (mean [standard deviation]) baseline adjusted Cmax was 1.99 (0.40) g/L, reached 1.76 (1.00) h after infusion, and half-life was 76.94 (20.21) h. Using ELISA, Cmax after FIB Grifols infusion was 2.88 (0.86) mg/mL, with a tmax of 3.06 (2.24) h. Fibrinogen activity and antigen concentrations showed statistically significant correlation of 0.9120 (P  Conclusions The pharmacokinetic profile of functionally active FIB Grifols was established, hemostasis was restored, and FIB Grifols was safe and well tolerated in fibrinogen-deficient patients.